For this week-in-review, it turns out I’ve got more questions than answers. Questions for you, in fact, the player/reader/steward of science.

Forums

I’m thinking of adding some forums to the site. The hope is, a forum would provide a nice place for science/game discussion. It’d be a spot to chat about:

The science in these games. Got a question about the relativity in Velocity Raptor, or about the math in the Gravity Simulator? Ask away!

The games themselves. Say you’ve made a picture in the Gravity Simulator, or created a level in Agent Higgs. Perhaps you’re stuck on a level and want some help. Maybe you have a feature you’re dying to see in a game. Bring it to the forum!

Science Games in general. There are a bunch of other neat science-y games out there in the world/internet. You’ve probably come across some that we need to check out. Share and share alike, I say.

Those are *my* thoughts, but I’d be interested to hear from you. What would you want out of a forum? Would you have any use for it? Leave your thoughts in the comments below.

Shockto-V3

The newest version of ~~The Electric Shocktopus~~! is ready. Let’s call it the ‘pre-alpha version 3.’ I’ve already got some helpful playtesters are giving it a trial run, which I’m so thankful for. If you’re interested in helping out, too, send me an email. When it comes to playtesters, the more feedback I get about the game, the merrier.

Gravity Simulator

With Shocktopus back out of my hands for the next week or so, I’m working on the Gravity Simulator again. There will be two big changes to the preexisting game. For starters, it won’t just be a flash game anymore, it will be playable on a bunch of devices — online, android, iOS, the whole gambit. Also, there are going to be a lot more features. You’ll be able to, say, change the colors of objects. Or add them easily along evenly-spaced grid lines. Or modify the celestial bodies mid-flight. All the things I’ve heard people say that ‘they’d love to see’ in the simulator. Is there something you’d like to see in the new update? What is the current simulator missing? Again, leave it in the comments, or send along an email.

On Monday, the ~~Electric Shocktopus~~! got its first (minor) debut. Still very much in the pre-alpha, work-in-progress stages, I brought it along to a local ‘demo night’ to show it off.

I dare you to get all three stars…

What’s a ‘demo night?’ Every few months in Boston, a bunch of indie game developers get together and play the games that we’re all working on. It’s a great chance to test our games in front of real players, and since many of those ‘players’ make games themselves, you can imagine the feedback is particularly insightful.

So what did I learn? Well, I found that some parts of the game were working great. People in general enjoyed the game, chuckled at the bad puns, and liked the cute Shocktopus. The game did turn out to be more difficult than I intended — so much so that I had to quickly go through and tweak some levels as the night went on. But all in all, people seemed to like the fact that it was a tough game. Like Super Meat Boy, generally when a player died they were ever-more determined to win.

Beyond all the comments I got at the Demo Night, it was also just a great deadline for me. In the week leading up to it, I added in a slew of new features to the game, including…

Zoomed in Levels

For intimate gatherings

A Level Editor

To make and change levels quickly

Puns, Puns, Puns

That pun, I do not think it means what you think it means

I’m already working on the next version, trying to take all the feedback from Monday into account. If you’re one of my helpful, helpful playtesters… I’ll be sending the new version along to you soon. And if you aren’t a playtester, but would like to be, just send me an email, and I can add you to the list.

“In the seen view of VR, the room shrinks/gets closer behind the raptor. But light should take longer to reach the raptor from behind him, so the view behind the raptor should be stretched out.”

So what’s up? A great question, and since it cuts to the core of the ‘Seen’ view (and requires some images) I thought I’d answer it in post form. If you haven’t played Velocity Raptor yet, do that first. This post will make a lot more sense once you reach level 25.

The basis for the ‘Seen’ view is that when you see something, the light from it didn’t reach your eyes instantly. Light travels fast, sure, but it takes time to reach you. So when you look at a star that’s many light-years away, you’re seeing it as it was many years ago. In Velocity Raptor, with slower light, you notice this even with nearby objects.

The commenter makes a perfectly intuitive point. If the light from an object takes longer to reach you, it would make sense that the object appears further away. The light from the moon takes longer to reach you than the light from your computer monitor, and it certainly appears further away. When you (as Velocity Raptor) are running away from, say, the left hand wall, there’s some extra lag for the light to reach you (check out Level 26, and keep the Doppler shift firmly in mind). So shouldn’t the wall appear further away? And yet on the screen, it appears much closer to you.

On the left, the raptor standing still. On the right, the raptor running to the right.

Why that doesn’t happen

It turns out that how far away an object appears to be doesn’t depend at all on how long the photons have been traveling towards you. Truly, your eyes can’t detect the ‘age’ of a photon. All your eyes detect are things like the color, and the angle the light is coming from. It’s that second one that tells our brain how big an object appears…

What’s really going on

You can think of your eye like a pinhole camera. Light rays from an object come in and get projected on the back wall (aka your retina). The closer — or bigger — an object is, the bigger the image on your retina.

The further the blue bar, the smaller the image cast on the retina.

When the raptor is running away from the wall, the eyeball is now moving away from the incoming light. That means the light that enters the eye has to travel further before it reaches the retina.

A stationary eye at the top, and a moving one on the bottom.

In the bottom image, the dotted-line box shows where the camera was when the light passed through the pinhole. The solid box shows where the camera is when the light finally hits the retina. It keeps the same angle of attack the whole time, but has longer to spread out, and makes a bigger image on the retina. Thus, the wall appears bigger. (Keep in mind that we should take length contraction into account… but that ends up being a second order issue. The effect I’ve described exists with or without length contraction.) This explanation, by the way, relies heavily on the great site spacetimetravel.org, which you should definitely check out if you want to learn more.

Now in 3D!

The question remains… does that mean the wall is closer, or does it mean the wall is bigger? If Velocity Raptor were from a first-person perspective (like A Slower Speed of Light), it wouldn’t make a big difference. In such a game you don’t see the distance of objects. An object could be small, or it could be far away. But with the bird’s-eye-perspective in Velocity Raptor, the distance needs to be drawn right on the screen.

It turns out the wall appears closer, instead of bigger. You can think about the true path of an object… if it is traveling in a straight line, you should always see it at some point along that path. Imagine standing on train tracks and watching the train race away from you. Should it appear bigger (wider and taller) than it is, or closer than it is? If it appeared wider, then the train would no longer seem to fit on the tracks. The wheels would be spaced to far apart. But the contact point of the wheel and the newly-run-over track must appear to be at the same place. The photons, after all, are emerging from the same location. Thus, the train cannot seem wider, and must seem closer.

So, excellent question, BARP, I hope this helps explain the ‘Seen’ view just a bit. Lingering questions/qualms with this explanation? Ask away in the comments below.

First off, many thanks to the play-testers that have helped out so far with ~~The Electric Shocktopus~~! With their help and feedback from the first version, I’ve been working on the next.

What have I been adding? For starters, more levels. That pre-alpha just had 15 levels, and the final game will be a lot longer. That means not only making new maps (which I have been), but also new mechanics. I’ve got to keep the game fresh as it goes on. Here’s a look at some of the latest.

Moveable Charges

(Hrm, these are in need of a catchier name.) While most of the charges in a level are purely stationary, these can move. Electrically push and pull them around, get them right where you want. Or if you’re not careful, they’ll attract right to you! See the test charge in the picture below for a glimpse at the idea.

Conductors

Not only can conductors sap your electric charge, they distort the fields around them. And they can ‘shield’ anything inside them from outside electric forces.

It’s like that test charge inside the box ~doesn’t even know~!

I’ve played around with a few different types of conductors. Some with a set voltage, and others that are ‘floating’. What does that mean? Oddly, it’s more important for the game than one might expect.

*Shocktopus shown for scale

In the picture above, the conductor is grounded — its voltage is precisely zero. The positive charges on the left attract extra negative charges into the conductor (from the ‘ground’). Field lines point from positive to negative, so there’s a whole bunch of lines pointing towards the conductor.

*Shocktopus not shown for scale

In the next image, though, the conductor is floating — aka not connected to the ground. Those red positive charges attract negative charges still, but no extra charges can appear. Thus, when the near side gets more negative, the far side of the conductor gets more positive. Thus, you see the field lines pointing towards *and* away from the conductor.

Biot-Savart

So far, the magnetic fields in the game have just been ‘on’ or ‘off’. Each square had a field, or it didn’t. But magnetic fields can be just as complex as electric fields… so I’ve added in some new current blocks that ‘make’ a magnetic field. The Biot-Savart law describes how an electric current can make a magnetic field (think of an electromagnet). The magnetic field varies with distance – just like the electric field – but it also varies with the angle. That means you can get the interesting pattern you see below.

The right hand rule means that pink squares are…?

This new version of the game still needs a lot of work, but it should be ready in the next week. As always, if you’re still interested in helping out by playtesting, drop me a line.

The new gravity simulator has been making some great progress. I’ve been spending a lot of time translating the game over to HTML5, and hoping it’ll be worth it. I can’t wait to see the game on tablets and mobile devices.

But, as always, it’s not so much about what progress I’ve made (zoom capability, fast loading times… uh, not-crashing), it’s about what progress I’ve made that *looks good in pictures.* So here are a couple new features that I’m excited about:

Color!

The old game always had white lines against a black background, but now you’ll be able to change that at will.

Go Pink, Go!

Dust Particles

In the old version, you could fling up to 7 asteroids. Now? No limit! Even more than that, there’s a new tool where you can put ‘dust particles’ into your solar system. Basically it’s a set of bodies with semi-random positions and velocities. Helpful for charting out the gravitational pull in your system… and also just plain cool.

Galactic dust mites are having a field day

So all in all things are moving along for the Gravity simulator. I’m still (as always) taking suggestions and comments about the old version and features you’d like to see in this new version.

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